The present invention relates generally to corrective knee structuring and pertains, more specifically, to apparatus and method for the surgical realignment of the knee through proximal tibial osteotomy.
The surgical management of conditions which result in knee misalignment, one of the most common of which is medial compartment osteoarthritis in the varus knee, includes total knee replacement, unicondylar knee replacement, and proximal tibial osteotomy. While each of these options may be appropriate in particular circumstances, it is preferable, especially in younger patients, to avoid implants and to opt for the less radical procedure of high tibial osteotomy. The most common technique for accomplishing the correction of knee misalignment through high tibial osteotomy currently is wedge osteotomy.
However, problems associated with wedge osteotomy render the procedure difficult to perform, lead to both short-term and long-term complications, and discourage both surgeons and patients from choosing the operation. Wedge osteotomy requires meticulous preoperative calculations and is a technically difficult operation. If the wedge osteotomy is not performed perfectly, a variety of problems can occur. Thus, over-correction and under-correction have been identified as common causes of poor results. Even with ideal correction at the time of surgery, alignment can change with time. Wedge osteotomy creates a mismatch between the bony surfaces of the osteotomy. The proximal side of the wedge is larger in surface area and is composed of primarily softer, cancellous bone, and a thinner metaphyseal cortex, while the distal side has a smaller area, thicker cortices, and less cancellous bone. Such a mismatch creates an abrupt lateral wall and increases the potential for long-term drift. Closing a wedge osteotomy creates other anatomic distortions such as lateral joint line deficiencies, distal joint lines, medial collateral ligament abnormalities, lateral ligament abnormalities, posterior cruciate ligament shortening, and patella infera.
Hence, while proximal realignment is considered to be the procedure of choice for younger patients, and especially those patients with medial compartmental osteoarthritis and varus knees, the early and late complications associated with wedge osteotomy have led many surgeons to avoid proximal tibial osteotomy altogether; however, others have sought alternative methods for achieving a reliable realignment through high tibial osteotomy. Among the most promising of these alternatives is dome osteotomy of the proximal tibia. Dome osteotomy demonstrates significant advantages over wedge osteotomy. Thus, because correction is achieved through a dome, rather than a wedge, there is no significant bone loss and anatomy is preserved. Accurate correction is attained more easily since change can be accomplished intraoperatively, in accordance with the surgeon's judgment, and can be verified in the operating room. The operation is accomplished through an anterior incision, avoiding complications associated with the lateral incision required in wedge osteotomy. The dome osteotomy does not create a significant mismatch between the proximal and distal fragments of the osteotomy. In fact, the relatively large surface area between the fragments promotes early and reliable healing. Since correction is achieved through a dome, both varus and valgus corrections are available. However, to be effective, dome osteotomy requires the reliable creation of an appropriate accurate dome.